Scientists Find Lasting Damage From Oil Spill

By JOHN NOBLE WILFORD

Published: January 10, 1989

IN the first comprehensive ecological study of oil spills in tropical waters, scientists have found that, contrary to widely held assumptions, the damage to coral reefs is not only immediate and severe but also can leave the organisms vulnerable to devastating disease and blight for years to come.

''The mythology was that there were few if any effects on coral,'' said Jeremy B. C. Jackson of the Smithsonian Tropical Research Institute in Panama, describing the biological consequences of a major oil spill in the Caribbean Sea off Panama in 1986. ''But we found rather dramatic effects.''

Dr. Jackson and other biologists reported last week that the mortality of coral organisms immediately after the spill was much higher than was expected on the basis of more limited studies in the past. Some experts, relying mostly on laboratory testing, had even declared that corals were not affected by oil residues.

The scientists also documented changes in the behavior and health of coral indicating that the organisms damaged by oil were probably more susceptible to epidemic disease and were likely to grow and reproduce at slower rates than unaffected colonies. These ''sublethal effects,'' the scientists concluded, ''are extensive and may be more important in the long term than initial mortality.'' Site of Marine Laboratory

The results of the first year and a half of the study were reported last week in the journal Science. The scientists said their project was the first to examine the aftermath of an oil spill in waters where the abundance and distribution of marine life had been well documented before the accident.

In April 1986 at least 80,000 barrels of crude oil leaked from a ruptured refinery tank and flowed into the Caribbean a few miles from the entrance to the Panama Canal. Much of the oil coated a coral reef and mangrove forest at Punta Galeta, which happened to be the site of the Smithsonian's marine laboratory and, therefore, had been the object of detailed environmental monitoring for more than 15 years.

This set the stage for the first definitive before-and-after study of the biological effects of a spill. Moreover, Dr. Jackson said in a telephone interview from Panama, nearly all previous investigations had concentrated on the fate of the oil rather than on the effects on marine biology.

Some of the findings were not particularly surprising. For example, the most extensive mortality from the spill was greatest in open sea, where oil tends to accumulate and settle into sediments. Not only were the mangroves themselves devastated, but the death toll was high for the mussels, oysters and other life among the mangrove roots.

Beyond the immediate deaths of organisms, the scientists said the reef was left with corals stripped of normal tissue. Algae and other organisms thus were colonizing the bare coral skeletons and setting in motion chain reactions that could lead to even more extensive damage. Dr. Jackson said he found a ''striking decrease'' coral growth rates.

The study, financed by the Department of the Interior, will be continued at least through 1991. Many of the affected coastal environments - seagrass beds, mangroves, algal flats and coral reefs - and most of the species involved are similar to those throughout the Caribbean and much of the Gulf of Mexico and the southern shores of the United States.